Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Requirement for one lead in any one hole

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Gus

#47167

Requirement for one lead in any one hole | 2 February, 2007

IPC standard 2221A for board design specifies that through hole leads shall be mounted such that there is only one lead in any one hole. Does anyone the reasons for this requirement?

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#47186

Requirement for one lead in any one hole | 3 February, 2007

Multiple leads in a single PTH is prohibited because: * Need to be able to remove and replace any component without impacting another. * Oversized hole required will result in increased solder defects and could also lead to flux entrapment. * Counteracting CTE of leads solder and TH materials. * Counter acting and tangential twist loads caused by the leads.

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